The goal of this clinical trial is to evaluate the safety and feasibility of patient-specific bone defect implants fabricated from Ti-6Al-4V using 3D printing technology and to assess early clinical outcomes within the first 12 months following implantation of these customized devices. The main question it aims to answer is: "In patients with bone defects requiring surgical reconstruction, are patient-specific bone defect implants fabricated from titanium alloy (Ti-6Al-4V) using 3D printing technology - designed and produced at VinUni, safe and feasible for clinical use, and do they result in favorable early clinical outcomes within the first 12 months following implantation?"